Thursday, February 13, 2014

Review paper finds the Medieval Warm Period in US was as warm or warmer than the present

A new paper from SPPI and CO2 Science comprehensively reviews the published scientific literature on the Medieval Warm Period in the contiguous United States, and concludes, "Solid empirical evidence continues to accumulate, demonstrating that (1) the Medieval Warm Period (MWP) was an interval of elevated global temperatures that were equally as warm as, and in many cases even warmer than, those of the Current Warm Period, and that (2) the MWP's elevated warmth was likely solar-induced, which suggests that the Current Warm Period may well be deriving its warmth from the same source, as it is likely nothing more than the most recent manifestation of the warm node of this ever-recurring climate cycle. That is simply not how the real world works; and this data-grounded fact provides a concrete reason for rejecting the projections of even the very best mathematical models of how earth's climate is supposed to operate, according to insufficient theoretical assumptions."

Climate alarmists claim that rising atmospheric CO2 concentrations due to the burning of fossil fuels, such as coal, gas and oil, have raised global air temperatures to their highest level in the past one to two millennia. And, therefore, investigating the possibility of a period of equal global warmth within the past one to two thousand years has become a high-priority enterprise; for if such a period could be shown to have existed, when the atmosphere's CO2 concentration was far less than it is today, there would be no compelling reason to attribute the warmth of our day to the CO2 released to the air by mankind since the beginning of the Industrial Revolution. Thus, in this review of the pertinent scientific literature, results of the search for such knowledge are presented for studies conducted within the confines of the lower 48 contiguous states of the United States of America.

On the basis of what they discovered, therefore, there appears to have been nothing unusual about the 20th-century climate of the San Francisco Bay area, because periods of both drought and wetness over the last hundred years of the past millennium were less extreme than similar periods of the preceding six centuries.

There is nothing unusual about the global warming of the past century or so, as it represents but the planet's natural recovery from the global chill of the Little Ice Age and the start of its return to Medieval Warm Period-like conditions.

There is nothing unusual about the global warming of the past century or so, as it represents but the planet's natural recovery from the global chill of the Little Ice Age and the start of its return to Medieval Warm Period-like conditions.

Once again, therefore, we have another example of a paleoclimate study in which the Medieval Warm Period was determined to have been significantly warmer than it is currently.

The fact that the deadly North American droughts of the MWP have never been equaled throughout all the ensuing years argues strongly that what Benson et al. call the anomalous warmth of that period has also "never been equaled throughout all the ensuing years," which further suggests (since the air's CO2 content was so much less during the MWP than it is now) that the lesser warmth of today need not in any way be related to the much higher CO2 concentration of earth's current atmosphere.

Solid empirical evidence continues to accumulate, demonstrating that (1) the Medieval Warm Period (MWP) was an interval of elevated global temperatures that were equally as warm as, and in many cases even warmer than, those of the Current Warm Period, and that (2) the MWP's elevated warmth was likely solar-induced, which suggests that the Current Warm Period may well be deriving its warmth from the same source, as it is likely nothing more than the most recent manifestation of the warm node of this ever-recurring climate cycle.